Melanocortin‐1 receptor (MC1R) genotypes do not correlate with size in two cohorts of medium‐to‐giant congenital melanocytic nevi

Congenital melanocytic nevi (CMN) are cutaneous malformations whose prevalence is inversely correlated with projected adult size. CMN are caused by somatic mutations, but epidemiological studies suggest that germline genetic factors may influence CMN development. In CMN patients from the U.K., genetic variants in MC1R, such as p.V92M and loss‐of‐function variants, have been previously associated with larger CMN. We analyzed the association of MC1R variants with CMN characteristics in two distinct cohorts of medium‐to‐giant CMN patients from Spain (N = 113) and from France, Norway, Canada, and the United States (N = 53), similar at the clinical and phenotypical level except for the number of nevi per patient. We found that the p.V92M or loss‐of‐function MC1R variants either alone or in combination did not correlate with CMN size, in contrast to the U.K. CMN patients. An additional case–control analysis with 259 unaffected Spanish individuals showed a higher frequency of MC1R compound heterozygous or homozygous variant genotypes in Spanish CMN patients compared to the control population (15.9% vs. 9.3%; p = .075). Altogether, this study suggests that MC1R variants are not associated with CMN size in these non‐UK cohorts. Additional studies are required to define the potential role of MC1R as a risk factor in CMN development.     

Subcellular localization of APE1/Ref-1 in human hepatocellular carcinoma: possible prognostic significance

APE1/Ref-1, normally localized in the nucleus, is a regulator of the cellular response to oxidative stress. Cytoplasmic localization has been observed in several tumors and correlates with a poor prognosis. Because no data are available on liver tumors, we investigated APE1/Ref-1 subcellular localization and its correlation with survival in 47 consecutive patients undergoing hepatocellular carcinoma (HCC) resection. APE1/Ref-1 expression was determined by immunohistochemistry in HCC and surrounding liver cirrhosis (SLC) and compared with normal liver tissue. Survival probability was evaluated using Kaplan-Meier curves (log-rank test) and Cox regression. Cytoplasmic expression of APE1/Ref-1 was significantly higher in HCC than in SLC (P = 0.00001); normal liver showed only nuclear reactivity. Patients with poorly differentiated HCC showed a cytoplasmic expression three times higher than those with well-differentiated HCC (P = 0.03). Cytoplasmic localization was associated with a median survival time shorter than those with negative cytoplasmic reactivity (0.44 compared with 1.64 years, P = 0.003), and multivariable analysis confirmed that cytoplasmic APE1/Ref-1 localization is a predictor of survival. Cytoplasmic expression of APE1/Ref-1 is increased in HCC and is associated with a lower degree of differentiation and a shorter survival time, pointing to the use of the cytoplasmic localization of APE1/Ref-1 as a prognostic marker for HCC.     

Progressive changes in the structure and dynamics of the phytoplankton community along a pollution gradient in a lowland river — a multivariate approach

The phytoplankton of the River Lujan (Buenos Aires, Argentina) was studied for a period of 18 months, together with physical and chemical variables, in relation to a pollution gradient. 167 taxa were recorded within a seasonal succession characterized by dominance of diatoms with a brief summer green algae facies. A combination of several biotic indices and multivariate analysis was employed to assess the impact of pollution on the phytoplankton community. The biotic indices used were species diversity and richness, algal quotients (green algae/diatom ratio, Centrales/Pennales ratio) and the SD succession rate index. Multivariate procedures included cluster analysis and ordination by PCA of both species and samples, stepwise discriminant analysis and multiple discriminant analysis of variance (MANOVA). Results indicate that community dynamism is attenuated at the more polluted sites, concomitant with an increased predominance of a broad-tolerance algal assemblage, co-dominated by Cyclotella meneghiniana and Nitzschia stagnorum. The changes in the community structure and dynamics described herein involved alterations in the distribution and relative proportions of the algae, rather than modifications in the basic species composition. These changes may not be readily detectable by methods which over-simplify the ecological information, such as systems of indicator species and biotic indices, designed to assess the degree of pollution. The suitability of multivariate analysis and biotic indices in river phytoplankton studies is further discussed.     

A proteomic approach to the bilirubin‐induced toxicity in neuronal cells reveals a protective function of DJ‐1 protein

Unconjugated bilirubin (UCB) is a powerful antioxidant and a modulator of cell growth through the interaction with several signal transduction pathways. Although newborns develop a physiological jaundice, in case of severe hyperbilirubinemia UCB may become neurotoxic causing severe long‐term neuronal damages, also known as bilirubin encephalopathy. To investigate the mechanisms of UCB‐induced neuronal toxicity, we used the human neuroblastoma cell line SH‐SY5Y as an in vitro model system. We verified that UCB caused cell death, in part due to oxidative stress, which leads to DNA damage and cell growth reduction. The mechanisms of cytotoxicity and cell adaptation to UCB were studied through a proteomic approach that identified differentially expressed proteins involved in cell proliferation, intracellular trafficking, protein degradation and oxidative stress response. In particular, the results indicated that cells exposed to UCB undertake an adaptive response that involves DJ‐1, a multifunctional neuroprotective protein, crucial for cellular oxidative stress homeostasis. This study sheds light on the mechanisms of bilirubin‐induced neurotoxicity and might help to design a strategy to prevent or ameliorate the neuronal damages leading to bilirubin encephalopathy.     

An automated assay for fecal estrogen conjugates in the determination of sex in avian species

Recently captive propagation of psitticines has become necessary in order to preserve and breed endangered species. As habitat destruction increases and importation restrictions become more stringent, the need for a reliable and noninvasive technique for sex assignment is essential to improve the productivity of breeding and raising birds in captivity. One aspect of breeding is the proper assignment of breeding pairs; however, sex identification can be challenging due to the lack of sexual dimorphism in approximately 30% of all avian species. Historically, visual, behavioral, surgical, cytogenetic, and endocrine methods have been utilized in sex identification of avian species; however, the practicality, safety, and reliability of these techniques have been questioned. Therefore, there remains a need for an accurate, simple, and non-invasive method to identify the sex of monomorphic birds so that the formation of breeding pairs and the success of breeding programs is facilitated. The data in this study support the concept that an automated fluorescence-immunoassay which measures fecal estrogen conjugates can have an 87% success rate in determining the sex of psitticines, as demonstrated with cockatiels, while offering the advantages of non-invasiveness, simplicity, and speed.     

Variation in phytoplankton composition and limnological features in a water–water ecotone of the Lower Paraná Basin (Argentina)

1. Structure and dynamics of phytoplankton were studied at six sites in a reach of the Lower Paraná River floodplain, from the main course to a marginal shallow lake, connected through a stream. This system is defined as a water–water ecotone and thus, the aim of this work is to analyse the spatial changes of phytoplankton along the transitional system.
2. Temporal fluctuations in number of species and phytoplankton density were more pronounced in the river than in the shallow lake. Even though most species were ubiquitous, there was a clear segregation of the most abundant populations across the ecotone. Aulacoseira granulata var. granulata and other centric diatoms decreased towards the lentic system.
3. Transparency varied according to river discharge, being higher in the lake during high water phases, while the opposite behaviour was observed during dry periods. These fluctuations were related to precipitation and resuspension processes.
4. Nitrate concentration diminished towards the lake while soluble reactive phosphorus remained fairly homogeneous across the ecotone.     

Comparison of the internal transcribed spacer, ITS-1, from Sarcocystis falcatula isolates and Sarcocystis neurona.

The genetic diversity among 6 Sarcocystis falcatula isolates derived from geographically distinct regions in the U.S.A. was detected using the first internal transcribed spacer region 1 (ITS-1) of the rRNA gene. These sequences were then compared to the full sequence from a Sarcocystis neurona isolate obtained from a California horse diagnosed with equine protozoal myeloencephalitis. No nucleotide differences were detected over partial sequence analysis of 2 additional S. neurona isolates: however, the complete nucleotide sequence for the ITS-1 region was not compared. Twelve nucleotide differences were consistently detected when aligned sequences of S. neurona were compared to those of the S. falcatula isolates. Additional nucleotide base changes were detected among the S. falcatula isolates, but these changes were not consistent in all the S. falcatula isolates. These results indicate that S. falcatula may be comprised of a heterogeneous population and that the ITS-1 region can be used to distinguish S. neurona from S. falcatala used in this study.